Influence of Canopy Configuration on Vegetative Development, Yield, and Fruit Composition of Seyval blanc Grapevines

¹ Department of Horticulture, Michigan State University, East Lansing, MI 48824.

Dept. of Horticulture and Landscape Architecture, Washington State Univ., Pullman, WA 99164-6414

Seyval blanc grapevines trained to three canopy configurations in 1988 were evaluated for vineyard perfor- mance, canopy development, and berry composition for a four year period. Treatments were: severe pruning (S; pruned to 8 nodes per 454 g cane prunings); full trellis (F; 45 nodes per vine); and hedge (H; hand pruned to a 10 cm radius around the cordon). The F and H vines filled the trellis area earlier, producing a greater leaf area through veraison; by harvest, S vines achieved a leaf area equal to the other treatments due to new leaf production from laterals. However, the H treatment produced canopies that required more time to cluster thin and contained poorly spaced shoots that were less winter hardy. The F and S vines produced many new leaves during fruit ripening, while the H vines did not. The F vines had higher yields than S and H vines, due to more berries per cluster and higher cluster weights, and were less affected by Botrytis bunch rot. There were no differences in fruit composition among treatments. Lower yield and the cost for controlling Botrytis bunch rot reduce the potential savings of severe pruning and mechanical hedging. Pruning Seyval blanc grapevines to 45 nodes properly spaced along the cordon, resulting in superior canopy development while increasing yield and cane quality and reducing Botrytis bunch rot.

Key words: pruning, mechanical hedging, shoot growth, leaf area, Botrytis bunch rot

Submitted on February 26, 1996